Re: mm: OS boot failed when set command-line kmemcheck=1

[Xishi Qiu]

On 2014/2/19 15:49, David Rientjes wrote:

> On Wed, 19 Feb 2014, Xishi Qiu wrote:
> 
>> Hi all,
>>
>> CONFIG_KMEMCHECK=y and set command-line "kmemcheck=1", I find OS 
>> boot failed. The kernel is v3.14.0-rc3
>>
>> If set "kmemcheck=1 nowatchdog", OS will boot successfully.
>>
> 
> I have automated kernel boots that have both "kmemcheck=0" and 
> "kmemcheck=1" as the last parameter in the kernel command line every 
> night and I've never seen it fail on tip or linux-next before.
> 
> So I'm sure I won't be able to reproduce your issue, but it may have 
> something to do with your bootloader that isn't described above.  The 
> sscanf() really wants to be replaced with kstrtoint().
> 
> Could you try this out?
> 
> diff --git a/arch/x86/mm/kmemcheck/kmemcheck.c b/arch/x86/mm/kmemcheck/kmemcheck.c
> --- a/arch/x86/mm/kmemcheck/kmemcheck.c
> +++ b/arch/x86/mm/kmemcheck/kmemcheck.c
> @@ -78,10 +78,16 @@ early_initcall(kmemcheck_init);
>   */
>  static int __init param_kmemcheck(char *str)
>  {
> +	int val;
> +	int ret;
> +
>  	if (!str)
>  		return -EINVAL;
>  
> -	sscanf(str, "%d", &kmemcheck_enabled);
> +	ret = kstrtoint(str, 0, &val);
> +	if (ret)
> +		return ret;
> +	kmemcheck_enabled = val;
>  	return 0;
>  }
>  

Hi David,

Thank you for your suggestion, but it still failed.
Here is a warning, I don't whether it is relative to my hardware.
If set "kmemcheck=1 nowatchdog", it can boot.

code:
	...
	pte = kmemcheck_pte_lookup(address);
	if (!pte)
		return false;

	WARN_ON_ONCE(in_nmi());

	if (error_code & 2)
	...

log:
[   10.920683] WARNING: CPU: 0 PID: 1 at arch/x86/mm/kmemcheck/kmemcheck.c:640 k
memcheck_fault+0xb1/0xc0()
[   10.920684] Modules linked in:
[   10.920686] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.0-rc3-0.1-default+
 #3
[   10.920687] Hardware name: Huawei Technologies Co., Ltd. Tecal RH2285 V2-24S/
BC11SRSC1, BIOS RMISV055 02/02/2013
[   10.920690]  0000000000000280 ffff88085f807678 ffffffff814ca491 ffff88085f807
6b8
[   10.920693]  ffffffff8104ce97 0000000000000000 ffff88085f807838 ffff88085f420
5d4
[   10.920695]  0000000000000000 0000000000000000 ffff88085f4205d4 ffff88085f807
6c8
[   10.920695] Call Trace:
[   10.920701]  <NMI>  [<ffffffff814ca491>] dump_stack+0x6a/0x79
[   10.920705]  [<ffffffff8104ce97>] warn_slowpath_common+0x87/0xb0
[   10.920707]  [<ffffffff8104ced5>] warn_slowpath_null+0x15/0x20
[   10.920710]  [<ffffffff810452c1>] kmemcheck_fault+0xb1/0xc0
[   10.920714]  [<ffffffff814d262b>] __do_page_fault+0x39b/0x4c0
[   10.920718]  [<ffffffff81272cd2>] ? put_dec+0x72/0x90
[   10.920720]  [<ffffffff812730ba>] ? number+0x33a/0x360
[   10.920723]  [<ffffffff814d2829>] do_page_fault+0x9/0x10
[   10.920726]  [<ffffffff814cf222>] page_fault+0x22/0x30
[   10.920731]  [<ffffffff81348b4c>] ? vt_console_print+0x8c/0x400
[   10.920733]  [<ffffffff81348b2c>] ? vt_console_print+0x6c/0x400
[   10.920737]  [<ffffffff8109cd9b>] ? msg_print_text+0x18b/0x1f0
[   10.920739]  [<ffffffff8109bed1>] call_console_drivers+0xc1/0xe0
[   10.920741]  [<ffffffff8109d746>] console_unlock+0x236/0x280
[   10.920744]  [<ffffffff8109e095>] vprintk_emit+0x2b5/0x450
[   10.920746]  [<ffffffff810452c1>] ? kmemcheck_fault+0xb1/0xc0
[   10.920748]  [<ffffffff814ca3f7>] printk+0x4a/0x4c
[   10.920750]  [<ffffffff810452c1>] ? kmemcheck_fault+0xb1/0xc0
[   10.920753]  [<ffffffff8104ce4e>] warn_slowpath_common+0x3e/0xb0
[   10.920755]  [<ffffffff8104ced5>] warn_slowpath_null+0x15/0x20
[   10.920757]  [<ffffffff810452c1>] kmemcheck_fault+0xb1/0xc0
[   10.920760]  [<ffffffff814d262b>] __do_page_fault+0x39b/0x4c0
[   10.920763]  [<ffffffff814d2829>] do_page_fault+0x9/0x10
[   10.920765]  [<ffffffff814cf222>] page_fault+0x22/0x30
[   10.920769]  [<ffffffff81015b52>] ? x86_perf_event_update+0x2/0x70
[   10.920772]  [<ffffffff8101de21>] ? intel_pmu_save_and_restart+0x11/0x50
[   10.920774]  [<ffffffff8101eb02>] intel_pmu_handle_irq+0x142/0x3a0
[   10.920777]  [<ffffffff814d0655>] perf_event_nmi_handler+0x35/0x60
[   10.920779]  [<ffffffff814cfe83>] nmi_handle+0x63/0x150
[   10.920782]  [<ffffffff814cffd3>] default_do_nmi+0x63/0x290
[   10.920784]  [<ffffffff814d02a8>] do_nmi+0xa8/0xe0
[   10.920786]  [<ffffffff814cf527>] end_repeat_nmi+0x1e/0x2e
[   10.920789]  [<ffffffff814cf0f0>] ? retint_signal+0x78/0x78
[   10.920791]  [<ffffffff814cf0f0>] ? retint_signal+0x78/0x78
[   10.920793]  [<ffffffff814cf0f0>] ? retint_signal+0x78/0x78
[   10.920799]  <<EOE>>  <#DB>  [<ffffffff81306b53>] ? acpi_ns_walk_namespace+0x
98/0x251


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